An antenna is a transducer which converts radio frequency (RF) energy to electromagnetic waves, and vice versa. As a transmitter, an antenna converts RF electrical current into electromagnetic waves. As a receiver, an antenna converts electromagnetic waves into RF electrical current. An electromagnetic wave has a polarization which is determined by its electric field plane.
Some antennae are linear polarized in that these antennae radiate (or receive) RF energy wholly in one plane containing the direction of propagation. An antenna is horizontally polarized when its electric field oscillates parallel to the ground surface of the earth. An antenna is vertically polarized when its electric field oscillates perpendicular to the ground surface of the earth.
A surface card antenna is one type of antenna. A surface card antenna is low profile, and can be mounted to a curved surface of a structure, such as a skin panel of an aircraft. It would be desirable to provide a surface card antenna which provides both the functionality of a horizontal polarization antenna and the functionality of a vertical polarization antenna.